1. Technical Field
This invention relates to communications networks, and in particular to a method for discovering SNMP agents on a communication network. Still more particularly, the present invention relates to a notification method which guarantees that a system manager discovers SNMP agents on a communications network.
2. Description of the Related Art
The technological development of communication networks is increasing at a fast pace. Network developers are continually searching for more efficient ways to complete network processes. A typical network consists of a web-like set of communication links to which are connected a plurality of agents. Agents on a network may be either a hardware device such as a router or a software application running on a processor system. Agents have traditionally been homogenous; however as networks become more complex, agents are becoming more and more heterogenous. As network complexity increases, it becomes more difficult to determine which agents are connected to the network.
A network could be a collection of voice, video, or data processing devices connected by communication lines. The method of transmission on the network is also key to determining the speed of transmission. Most present network connections utilize the Transmission Control Protocol/Internet Protocol (TCP/IP) as their transmission medium. The agents connected to these networks, in turn, utilize a Simple Network Management Protocol (SNMP), and are referred to as SNMP agents.
Networks are thus managed by a network management tool or network manager. A network manager is connected to one of the links of the network and utilized to monitor and manage the network""s links, agents, and network functions. To provide effective management, the network manager must therefore be aware of which agents are connected to the network in order to efficiently monitor the agent processes. Additionally, a network manager needs management information about the network to help conceptualize the network and call attention to adverse changes in a fast and accurate manner.
Agent discovery process is therefore one important element to consider in the design of a network and the network manager. When a new agent is connected or a previously connected agent is reconnected, the network management station has to be made aware of the presence of the agent. A standard approach in discovering SNMP agents by a system manager is to broadcast a query message over the network and wait for acknowledgment. U.S. Pat. Nos. 5,933,416 and 5,835,720 utilize this broadcast query and acknowledgment method. This standard approach floods the network with its broadcasting message. Also, with this method, some SNMP agents may respond and some may not for various reasons. As a result there is no guarantee that all agents will be discovered.
Most current networks are configured with TCP/IP. The network management protocol of TCP/IP is Simple Network Management Protocol (SNMP). In SNMP, agents, which can be hardware as well as software, monitor the activity in the various devices on the network and report to the network manager. Control information about each device is maintained in a management information block.
Another prior art method utilizes a simple polling approach to gather network information. This method has severe problems in wasting network bandwidth, as described in Rose, xe2x80x9cThe Simple Book,xe2x80x9d p. 76, Englewood Cliffs, N.J. Prentice Hall Inc. This is of special concern in wide-area networks where recurring transmission line expenses directly affect the cost of network operation. Bandwidth used by management traffic comes at the expense of user bandwidth. Even in broadband networks, such as ATM networks, minimizing management bandwidth usage is a concern.
U.S. Pat. No. 5,909,549 describes a method which allows the SNMP managed device (agent) to register with a Network manager by generating and transmitting a frame. The process of transmitting the frame continues until the management station responds with another frame acknowledging receipt. That system further has a timer which determines when a follow up frame should be sent if the frame acknowledging receipt is not sent to the managed device. Like the traditional methods, this method results in a clustering of network resources with management frames utilizing valuable bandwidth. Also, the method requires a user to send a proprietary form of frame (trap) to communicate with the network manager and involves a series of unnecessarily complicated handshakes to complete the process. Further this method is system specific, i.e., it does not allow the discovery of different types of agents as in heterogenous networks. Further, like other prior art methods it results in a low success rate of discovery.
To build and continuously update a reliable network, information must be collected from each network node. The challenge is to do this in real time without adversely consuming network bandwidth, while increasing the success rate of agents discovery.
The present invention recognizes that it is advantageous to have a method and system for efficiently discovering an SNMP agent on a network without using significant amounts of bandwidth or incurring the potential errors of the broadcast query and acknowledgment method. The present invention substantially reduces or eliminates the potential for errors by having the agents themselves notify the network manager and thus increasing the success rate of discovery.
It is therefore one object of the present invention to provide an improved communications network.
It is another object of the present invention to provide an improved method for discovering SNMP agents on a communications network.
It is yet another object of the present invention to provide a method for efficiently discovering SNMP agents on a communications network by having the agents notify the network manager directly.
The foregoing objects are achieved as is now described. A method for a guaranteeing a network manager discovers SNMP agents on a communications network is disclosed. Each SNMP agent transmits a trap via network links to the network manager. The trap contains the network manager""s IP address and the agents identifying information, such as its IP address. When the trap is received at the network manager, it is parsed for the agent identifying information, which is compared against the list of previously identified/discovered agents. If the agent identifying information is not found, which indicates that it is a newly discovered agent, the network manager adds the agent to the list of discovered agents on the network. The agent is then registered/stored in the discovered agent file. When the trap does not include sufficient identifying information, the network manager sends a query to the agent to extract additional identifying information. The system manager is thus able to discover all connected agents over a period of time without having to broadcast a query message or unnecessarily flood the network with traffic.
The above as well as additional objects, features, and advantages of the present invention will become apparent in the following detailed written description.